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SubjectRe: [PATCH] powerpc/fsl-pci: Fix Class Code of PCIe Root Port
PING?

On Wednesday 06 July 2022 12:10:43 Pali Rohár wrote:
> By default old pre-3.0 Freescale PCIe controllers reports invalid PCI Class
> Code 0x0b20 for PCIe Root Port. It can be seen by lspci -b output on P2020
> board which has this pre-3.0 controller:
>
> $ lspci -bvnn
> 00:00.0 Power PC [0b20]: Freescale Semiconductor Inc P2020E [1957:0070] (rev 21)
> !!! Invalid class 0b20 for header type 01
> Capabilities: [4c] Express Root Port (Slot-), MSI 00
>
> Fix this issue by programming correct PCI Class Code 0x0604 for PCIe Root
> Port to the Freescale specific PCIe register 0x474.
>
> With this change lspci -b output is:
>
> $ lspci -bvnn
> 00:00.0 PCI bridge [0604]: Freescale Semiconductor Inc P2020E [1957:0070] (rev 21) (prog-if 00 [Normal decode])
> Capabilities: [4c] Express Root Port (Slot-), MSI 00
>
> Without any "Invalid class" error. So class code was properly reflected
> into standard (read-only) PCI register 0x08.
>
> Same fix is already implemented in U-Boot pcie_fsl.c driver in commit:
> http://source.denx.de/u-boot/u-boot/-/commit/d18d06ac35229345a0af80977a408cfbe1d1015b
>
> Fix activated by U-Boot stay active also after booting Linux kernel.
> But boards which use older U-Boot version without that fix are affected and
> still require this fix.
>
> So implement this class code fix also in kernel fsl_pci.c driver.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Pali Rohár <pali@kernel.org>
> ---
> arch/powerpc/sysdev/fsl_pci.c | 8 ++++++++
> arch/powerpc/sysdev/fsl_pci.h | 1 +
> 2 files changed, 9 insertions(+)
>
> diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
> index 1011cfea2e32..bfbb8c8fc9aa 100644
> --- a/arch/powerpc/sysdev/fsl_pci.c
> +++ b/arch/powerpc/sysdev/fsl_pci.c
> @@ -521,6 +521,7 @@ int fsl_add_bridge(struct platform_device *pdev, int is_primary)
> struct resource rsrc;
> const int *bus_range;
> u8 hdr_type, progif;
> + u32 class_code;
> struct device_node *dev;
> struct ccsr_pci __iomem *pci;
> u16 temp;
> @@ -594,6 +595,13 @@ int fsl_add_bridge(struct platform_device *pdev, int is_primary)
> PPC_INDIRECT_TYPE_SURPRESS_PRIMARY_BUS;
> if (fsl_pcie_check_link(hose))
> hose->indirect_type |= PPC_INDIRECT_TYPE_NO_PCIE_LINK;
> + /* Fix Class Code to PCI_CLASS_BRIDGE_PCI_NORMAL for pre-3.0 controller */
> + if (in_be32(&pci->block_rev1) < PCIE_IP_REV_3_0) {
> + early_read_config_dword(hose, 0, 0, PCIE_FSL_CSR_CLASSCODE, &class_code);
> + class_code &= 0xff;
> + class_code |= PCI_CLASS_BRIDGE_PCI_NORMAL << 8;
> + early_write_config_dword(hose, 0, 0, PCIE_FSL_CSR_CLASSCODE, class_code);
> + }
> } else {
> /*
> * Set PBFR(PCI Bus Function Register)[10] = 1 to
> diff --git a/arch/powerpc/sysdev/fsl_pci.h b/arch/powerpc/sysdev/fsl_pci.h
> index cdbde2e0c96e..093a875d7d1e 100644
> --- a/arch/powerpc/sysdev/fsl_pci.h
> +++ b/arch/powerpc/sysdev/fsl_pci.h
> @@ -18,6 +18,7 @@ struct platform_device;
>
> #define PCIE_LTSSM 0x0404 /* PCIE Link Training and Status */
> #define PCIE_LTSSM_L0 0x16 /* L0 state */
> +#define PCIE_FSL_CSR_CLASSCODE 0x474 /* FSL GPEX CSR */
> #define PCIE_IP_REV_2_2 0x02080202 /* PCIE IP block version Rev2.2 */
> #define PCIE_IP_REV_3_0 0x02080300 /* PCIE IP block version Rev3.0 */
> #define PIWAR_EN 0x80000000 /* Enable */
> --
> 2.20.1
>

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